Use of cu-as-se glass to transmit long wavelength radiation

ABSTRACT

An infrared transmitting glass produced by adding Cu to a chalcogenide glass in an amount of 12 - 40 atomic percent of the latter.

Elite States Patent 1 [1 1 Asahara et a1.

[4 1 Oct. 15, 1974 USE OF CU-AS-SE vGLASS TO TRANSMIT LONG WAVELENGTH RADIATION lnventorsz- Yoshiyuki Asahara, Kanagawa;

Tetsuro lzumitani, Tokyo, both of Japan Hoya Glass Works, Ltd, Tokyo, Japan Filed: Apr. 27, 1973 Appl. No.: 354,975

Assignee:

Foreign Application Priority Data Oct. 2, 1972 Japan 47-98807 U.S. CI 350/320, 106/47 R, 252/300, 350/1 Int. Cl. G03c 3/24, G021) 1/00 Field of Search 106/47 R; 350/1; 1 17/201, 117/106 A; 252/300; 65/134 References Cited UNITED STATES PATENTS 10/1966 Schneeberger 350/1 TRANSMISSIGN RAW} 1%) e e WAVELENGTH (111 3,657,006 4/1972 Fisher et a1. 106/47 UX OTHER PUBLICATIONS Primary Examiner-I-lelen M. McCarthy Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [5 7 ABSTRACT An infrared transmitting glass produced by adding Cu to a chalcogenide glass in an amount of 12 40 atomic percent of the latter.

1 Claim, 1 Drawing Figure PAIENTEU 1 5 WAVELENGTH (u) USE OF CU-AS-SE GLASS TO TRANSMIT LONG WAVELENGTH RADIATION 1 BACKGROUND OF THE INVENTION As-Se or Ge-As-Se glasses especially transmit light having a wavelength shorter than 15 pt. These two glasses .are very stable and exhibit good chemical durability.

However, various-oxides are present in chalcogenide 2 DETAILED DESCRIPTION OF THE INVENTION The amount of Cu is restricted in the above described range of 12 40 atomic percent for the following reason. If the Cu content in the chalcogenide glass is not more than 12 atomic percent, the effect of the Cu addition to increase the transmission near 12.8 it and 16 u is not fully realized. On the other hand,- more than 40 atomic percent of Cu introduced into the chalcogenide glass causes the glass to be unstable.

Observing. the above limits on the Cu, preferred glasses contain to 60 atomic percent As and 25 to 60 atomic percent Se.

As is known in the art, the chalcogenide glasses are those which contain at least one of S, Se and Te.

Some examples of the effect of the Cu addition to the chalcogenide glass will be shown in the following Table with reference to an As-Se glass. A

Specimen Composition Softening Percent Thickness of No. (atomic point transmission the specimen As Se Cu (C) 12.8u 16.0u (mm) 1 40 60 210 0 0 0.772 1' 40 60 do. 5.0 1.0 0.191 2 50 50 200 0 0 0.773 2' 50 50 do. 3.5 1.5 0.297 3 60 40 150- 0 0 0.734 4 36 54 10 195 1.7 0.2 0.665 5 28 42 225 11.0 7.0 0.665 6 26 39 235 8.0 4.6 0.815 7 32 48 20 23.0 16.0 0.173 8 55 30 15 38.0 34.0 0.240 9 45 30 25 37.0 35.0 0.285 10 35 35' 30 33.0 30.3 0.277

Specimens l 4 are'comparative according to this invention.

glasses which inhibit the transmission of infraredrays.

More particularly, As is easily oxidized and causes abcesses are necessary for the production of As containing chalcogenide glasses, although As increases the softening point, the thermal strength and the chemical durability of the resulting glass.

SUMMARY OF THE INVENTION This invention is based on the discovery that the ad- 'dition of Cu to a chalcogenide glass reduces the absorption light in the neighbor of 12.8 t and 16 p. in a chalcogenide glass. If 12 atomic percent of Cu is added to the chalcogenide glass, the infrared transmitting edge at thelonger wavelength side increases to 20 p.,

and the necessary critical control of the refining, melting and forming of the raw material can be eliminated. In addition, the softening point of the resulting glass can be increased and. the thermal properties are'improved.

f BRIEF DESCRIPTION OF THE'DRAWING The FIGURE shows the relationship between relative transmission of light and the wavelength of the light,

where curve 1 shows the relationship for a Cu-free As-Seglass and curve 2 shows the relationship for an As-Se glass containing 25 atomic Cu.

glass compositions. and specimens 5 10 are glass compositions The percent transmission of each glass specimen is measured at 12.8 p. and at 16.0 n. The test results show that the transmission increases when the Cu content exceeds l0 atomic percent.

In the drawing, curve 1 shows the relationship between the transmission ratio and the wavelength of the light forSpecimen 1', and curve 2 shows the relationship for Specimen 9. It will be apparent from these two curves that the absorption of the light at 12.8 p. and at 16.0 p. is extinguished by the Cu addition. In addition, it is apparent that thesoftening point of the glass gradually increases and the thermal properties improve with increase of the Cu content, (e.g., compare Specimens 1 and 4 with Specimens 5 and 6).

Each specimen was produced by charging a mixture of unrefined ingredients, i.e., As (99.9 percent pure), Cu (99.99 percent pure) and Se (99.99 percent pure), into an evacuated quartz tube, melting the mixture thereinat 800 900C for 2 3 hr., cooling in atmospheric air and then taking the product out of the quartz tube and grinding the cooled glass to the desired thickness.

Although this invention has been described with referen'ce to the preferred embodiments thereof, it will be understood to one skilled in the art that the numerous modifications may be made without departing from the scope and spirit of this invention.

What is claimed is:

1. The process of using a glass consisting of 1240 atomic percent of Cu, 25-60 atomic percent of As and 25-60 atomic percent of Se to transmit infrared radiation at 12.8 and 16 microns and up to a transmitting edge of 20 microns. 

1. THE PROCESS OF USING A GLASS CONSISTING OF 12-40 ATOMIC PERCENT OF CU, 25-60 ATOMIC PERCENT OF AS AND 25-60 ATOMIC PERCENT OF SE TO TRANSMIT INFRARED RADIATION AT 12.8 AND 16 MICRONS AND UP TO A TRANSMITTING EDGE OF 20 MICRONS. 